Elucidating the Role of Very-long-chain Polyunsaturated Fatty Acids in Retinal Health and Disease

阐明极长链多不饱和脂肪酸在视网膜健康和疾病中的作用

• 批准号: 10566152
• 负责人: PAUL STEVEN BERNSTEIN
• 金额: $ 40.44万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10566152
• 关键词: Acute; Age related macular degeneration; Animal Model; Animals; Attention; Biophysics; Bypass; CRISPR/Cas technology; Cell Culture Techniques; Cell membrane; Cell model; Chemistry; Chronic; Clinical Research; Collaborations; Consumption; Data; Development; Diet; Dietary Fatty Acid; Disease; Dominant-Negative Mutation; Dryness; Environment; Exhibits; Family; Fatty Acids; Functional disorder; Health; Heterozygote; Human; Human body; Knock-out; Lead; Lipid Chemistry; Lipids; Macular degeneration; Maintenance; Membrane; Membrane Fluidity; Methodology; Modeling; Mus; Mutation; Neonatal; Nonexudative age-related macular degeneration; Oral Administration; Organism; Organoids; Patients; Permeability; Phenotype; Photoreceptors; Polyunsaturated Fatty Acids; Process; Proteins; Protocols documentation; Publishing; Reporting; Research; Retina; Risk; Role; Scheme; Skin; Specialist; Stargardt' s disease; Structural defect; Supplementation; Synaptic Transmission; System; Testing; Therapeutic; Therapeutic Intervention; Tissues; Universities; Utah; Variant; Vertebrate Photoreceptors; Very Long Chain Fatty Acid; Wild Type Mouse; Zebrafish; autosomal dominant mutation; autosome; biophysical properties; conditional knockout; dietary; disorder of macula of retina; experimental study; fatty acid metabolism; fatty acid supplementation; feeding; fluidity; functional improvement; human tissue; improved; insight; macula; membrane model; mouse model; novel; novel strategies; novel therapeutic intervention; photoreceptor disc; protective effect; research study; response; scale up; tool; visual motor; visual performance

Very long-chain polyunsaturated fatty acids (VLC-PUFAs) are non-dietary lipids that are uniquely found in the retina and just a few other tissues in the human body. These unusual C26-C38 n-3 and n-6 lipids are synthesized from long-chain polyunsaturated fatty acid (LC-PUFA) dietary precursors through the action of the ELOVL4 fatty acid elongase. Enhanced membrane fluidity contributed by LC-PUFAs and VLC-PUFAs is thought to be essential for the maintenance of the highly curved membrane disks of the photoreceptor outer segments and to facilitate photoreceptor synaptic transmission. Autosomal dominant mutations in ELOVL4 lead to a form of Stargardt macular dystrophy (STGD3) that shares many features with dry age-related macular degeneration (AMD), and we and others have shown that conditional knockouts of rod and cone Elovl4 lead to depletion of retinal VLC-PUFAs and eventual retinal functional and structural abnormalities in mouse models. Although ELOVL4 variants have not been associated with AMD risk, the protective effects of diets high in lipid precursors of n-3 VLC-PUFAs against STGD3 and AMD led to us to examine the influence of diet on retinal VLC-PUFA levels and n-3/n-6 ratios in health and disease. We have reported that dietary consumption of VLC-PUFA precursors strongly influences n-3/n-6 ratios and VLC-PUFA content in normal human retinas and that VLC-PUFA profiles are distinctly abnormal in AMD donors even outside of the macula. These findings suggest that abnormalities of VLC-PUFA metabolism are intimately associated with macular degeneration and that strategies to increase VLC-PUFA levels by supplementation could help slow the degeneration process. Surprisingly, the obvious therapeutic intervention of bypassing local retinal synthesis of VLC-PUFAs by administering preformed VLC-PUFAs exogenously had never been tried in living organisms because, until recently, there have never been adequate supplies of these lipids to perform these experiments, even in mice. Although synthesis of VLC-PUFAs has been reputed to be very difficult, we initiated a collaboration with lipid chemistry specialists at the University of Utah who developed improved schemes that allow for straightforward scale-up to produce sufficient quantities of pure n-3 and n-6 VLC-PUFAs (unlabeled, fluorinated, or deuterated) for animal studies and even eventual human trials. We have generated exciting initial data that show that an orally administered synthetic VLC-PUFA (32:6 n-3) is selectively targeted to the retina and the RPE after acute and chronic gavage feeding in mice and that wild-type mice and a mouse model of VLC-PUFA dysfunction show functional improvements in their ERGs and visual performance. With our unique access to sufficient quantities of an array of n-3 and n-6 VLC-PUFAs, we are eager to continue to test our fundamental hypothesis that VLC- PUFAs are key compounds for the maintenance of photoreceptor function in the retina in both health and disease states. We will do this by more fully exploring the mechanisms underlying the protective effects of exogenous VLC-PUFAs in the retina and RPE in novel animal models, in cell culture, and in model membranes.

超长链多不饱和脂肪酸(VLC-PUFAs)是唯一发现的非膳食脂肪 在视网膜和人体的其他几个组织中。这些不寻常的C26-C38n-3和n-6脂类是 从长链多不饱和脂肪酸(LC-PUFA)饮食前体合成通过作用 ELOVL4脂肪酸延伸酶。认为LC-PUFAs和VLC-PUFAs有助于提高膜的流动性 对于维持感光细胞外节高度弯曲的膜盘是必不可少的 并促进光感受器突触的传递。ELOVL4常染色体显性突变导致一种形式 Stargardt黄斑营养不良症(STGD3)与干性老年性黄斑变性有许多共同特征 (AMD)，我们和其他人已经证明，杆和锥体ELOVL4的有条件敲除会导致 视网膜VLC-PUFAs和最终的小鼠视网膜功能和结构异常。 尽管ELOVL4变异与AMD风险没有关联，但饮食的保护作用很高 在脂质前体中，抗STGD3和AMD的VLC-PUFAs使我们研究了饮食对 健康和疾病患者视网膜VLC-PUFA水平及n-3/n-6比值。我们已经报道过，饮食消费 VLC-PUFA前体的含量强烈影响正常人视网膜n-3/n-6比值和VLC-PUFA含量 AMD供者的VLC-PUFA谱明显异常，甚至在黄斑部以外也是如此。这些发现 提示VLC-PUFA代谢异常与黄斑变性密切相关。 通过补充来提高VLC-PUFA水平的策略可能有助于减缓退化过程。 令人惊讶的是，绕过局部视网膜合成VLC-PUFAs的明显治疗干预是通过 外源注射预制的VLC-PUFA从未在活体中被尝试过，因为直到 最近，从来没有足够的这些脂质供应来进行这些实验，即使是在小鼠身上。 尽管VLC-PUFAs的合成一直被认为是非常困难的，但我们与LID开始了合作 犹他大学的化学专家，他开发了改进的方案，允许直接 放大生产足够数量的纯n-3和n-6 VLC-PUFA(未标记、氟化或氢化) 用于动物研究，甚至最终的人体试验。我们已经生成了令人兴奋的初始数据，这些数据表明 口服合成VLC-PUFA(32：6n-3)后，选择性地靶向视网膜和RPE 小鼠的慢性灌胃喂养和野生型小鼠和VLC-PUFA功能障碍的小鼠模型显示 他们在ERG和视觉表现方面的功能改善。通过我们独特的途径获得足够的数量 对于n-3和n-6个VLC-PUFA的阵列，我们渴望继续测试我们的基本假设，即VLC- 在健康和疾病中，多不饱和脂肪酸都是维持视网膜光感受器功能的关键化合物 各州。我们将通过更充分地探索外源激素保护作用的潜在机制来实现这一点。 新型动物模型、细胞培养和模型膜中视网膜和RPE中的VLC-PUFAs。